Oil-cracking process



MarchZS, 1930.v 1B. JAQUA OIL CRACKING PROCESS Filed Nov. 26,

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,4free/ver l Patented 'Mar'. 2,5,y 193Q `\E UNITED* sv'rATEs PATENTOFFICE JOHN B. JAQUA, OF ALHAMBRA, CALIFORNIA OIL-CRACKING PROCESSApp/liaton l'ed November 26, 1926. Serial No. 150,762.

y Although my present invention is entitled, somewhat broadly, asreferring to an oil cracking process, it should be understood that thisinvention relates more particularly to a process in which mineral oil iscracked mainly orentirely while in the liquid state or phase; and themostk unique feature of my invention may be the technique by whichimpart'heat to crude or other oil, for crack-I 10 ing or analogouseffect.

By the use of a novel process and apparatus which it is an object lofthis invention to provide, I avoid or reduce to a minimum such localoverheating of pipes, or the like, as tends to produce carbon depositstherein; I preferably adda non-aqueous heat-transferring fluid inincrements, at successive stages of conversion, maintaining atemperature for a predetermined time and obviating the use of an undulyhigh initial temperature and I maintain in heating'and cracking coils avelocity of flow sufficient to carry forward such carbon as mayinevitably result from the heating and/or cracking operations effectedthereinw AsY pertinent to the main problems which it is an object of myinvention to solve, I

quote the following from a work entitled Gasoline andAv Other MotorFuels, by Ellis and Meigs (Van Nostrand Company, 1921, page 431) Manyinvestigators have realized that overheating an oil has a tendency todecompose it into fixed gases and carbon. For example, by forcing oilthrough red hot pipes it is possible almost completely to break the oilup into fixed carbon and gas, without `the formation of any naptha, ifthe vapors remain long enough in contact with the heated surfaces. Withdirect firing. overheating,

is sometimes difficult to avoid. With this in view, many processes havebeen proposed for maintaining a mreuniform temperature byv means offused baths of imetals or salts.

Although some of the results of my inventionimay be obtained by usingfused baths of metals or salts, it is an object of my invention to `gainthe essential advantages thereof, and additional advantages, by simolerand/or superior means; and, in preferred embodiments ofo my invention,using a comparatively stable oil (such as a thermolyzed gas oilobtainable as.bottoms) for a heat-transferring eect, and heating thismedium to a temperature somewhat above that desired to effect anendothermic reaction of the raw mineral oil (such as a crackingreaction) I deliver the mentioned heat-transferring fluid, or itsequivalent, in the form of separate small streams thereof, fed atsuccessive points, into an advancing stream of the oil within which thementioned reaction is to be produced i-the latter oil being prefermeansand methods permitting thermolyzed and relatively stable oil fractionsto be repeatedly returned' and used as cycle stock) in such manner thatthey may not only serveA for a heat-transferring effect but maythemselves gradually become decomposed into lighter products, andincluding also novel yfeatures of interconnection and organization ofapparatus as herein described, may be best appreciated from thefollowing description of illustrative embodiments of my invention, takenin connection with the ap- /Rpended claims and the ,accompanying draw-HSIs, in which- #The figure may be referred to as an entirelydiagrammatic elevational view, with parts broken away, of an apparatussuitable for use in the practice of my invention.

Referringto the illustrated embodimentof my invention,'I show a crackingcoil 11 as comprising a series of separate sections 11, 1lb, 11,J l1dand lle, this coil being preferably entirely unprovided with means for adirect heating thereof, and being shown as provided'w'ith a supply pipe12, for the mineraly oil in which a cracking or other endothermicreaction is d'esired.-

Although it is an object of my inventiori) as indicated above, toobviate, so vfar as possible, the deposition of carbon or heavy residuesWithin cracking apparatus, in view of the factthat, generally speaking,oils may be'hrought near to their cracking temperatures Without suchdeposition, I may interpose in the supply pipe 12, or its equivalent, apreliminary or primary heater of any preferred type, such as that shownat 13 as comprising` a coil of pipe exposed to direct or indirectheating -15 by a flame 14,-oil being fed thereto by means such as a pump15, assumed lto operateat a rate consistent with the opening of valvessuch as are indicated at 16 and 17 .l

After the oil is fed through the preliminary I heater 13 and thereinheated, in the described anner or in an equivalent manner, to atemypeature slightly below that which may be pre-requisite toacracking'or other desired physical or chemical effect, I prefer to addthereto the heat required -for obtaining such effect by introducing, asby Way of a manifold 18 and separately valved branch pipes 18a,18b,'18c, 18I and 18e, a liquid heat-trans ferring medium, such as arelatively stable oil, heated to a .temperature slightly above' thatrequired to effect th'evdesired physical and/or chemical change in thetreated oil,x as the same is introduced through the supply j pipe `12and` advanced through coil-11; and the mentioned stableoil, or itsequivalent, may accordingly be brought-to the desired high temperatureby 'means such'as a' so-called superheater or storage heater'19. shownas constructed similarly lto the mentioned preliminary or primary heater13 and as heated by a flame 20,-a coil comprised in the mentionedsuperheater being shown as connected with the manifold 18 byrflvalvedpipe 21.;

The cracking coil-11 being shown as provided with an. outlet 2 2, inwhich I prefer to interpose a pressure-reducing valve 23, said outletmay terminate, at an intermediate level, in a separator or in aninterposed vaporizer 24,-t-his being shown as provided l with a vaporoutlet 25,--through which mayVL pass such volatile products as areproduced by the mentioned cracking reactionsvithin the coil 11; andthermolyzed residuum andffor heavy intermediate fractions may beWithdrayvn through aobottom outlet 26 and/ox" through an additionalvalved outlet, suoli as that shown'at 27 as connected withsaid'vaporizer' atl an intermediate level.

Although Il 'showbothof theI outlets 26 9 and 27 as connectedwithareturn pipe 28 'by which, uponrthe operation of a pump 29, aresidue delivered through either of lsaid pipes ,-or a mixture of lsuch.residues, may bel 'ireturned through a pipe' 3() to the sup'erheater 5519, Show saidputlet pipes' as also communi- -suchas a crude or toppedoill(assumed to feet during its J j eating, by valved branches31`and.32,iwvith a pipe 33,-shown as valved at 34 in a manner permittingthe Withdrawal of said residue or any comparatively non-volatileproduct; but

I` prefer ordinarily to supplement the action of the so-called vaporizer24 by the. use of an additional element, somewhat similar inconstruction connectiomsuch as separator 35. This is shown as connected,at an intermediate level, with the vapor pipe 25, and as provided With apressure-reducing valve 36 in what I may term a final vapor outlet 37for desired distillates. f

Assuming that the vaporizer 24 ami the separator 35 are to be operatedat dill'erent` temperatures and pressures, aLnd in order to ,accomplishlboth a condensing effect in these elements and an initial heating of rawoil to be-fed by the pump 15, or its equivalent, I may carry the raw oilpipe 12, or -its equivalent, through either or -both of the mentionedelements 24 and 35, as by providing coi-ls 38 and 39 therein (bubbleplates being optionally interposed,` asat 40, in both or one of saidelements) and I may also interpose in the vapor pipe 25,-or itsequivalent, a pressure-reducing valve'41.

The separator 35, orits equivalent, being intended, when thus employed,to receive only such hydrocarbons as have passed 95 through the vaporpipe 25, I` need ordinarily make, in connection with saidI separator, noprovision for the Withdrawal of such heavy residues as may be dischargedfrom the vaporizer 24, past the valve 34 in pipe 33; but 100 Inevertheless shou7 the said separator as provided with a,bottom` outlet42 (communicating both directly yand indirectly with the mentionedreturn pipe 28) and also with a .lateral outlet 43. The outlet 43 maydeliver any desired intermediate fraction, by Way of :a valved pipe 34(with which the mentioned pipe 33, from vaporizer 24 may be connected bytvalved lateral 44) into a tank not shown; and the outlet 42 is shown asprovided With a valved branch 42- leading to a storage tank 45. Thelater is shown as connected by anoutlet pipe 46 (in which a pumpl 47 maybe interposed) with the mentioned return pipe'28,-this arrangementadapting 115 said tank to serve for a make-up purpose hereinafterreferred to.

In the ordinary use of an apparatus of the general character described,aV raw material contain littleor nothing of a gasoline frac-- tion) maybe continuously admitted into the inlet end 12a of the pipe 12, or` itsequivalent, receiving heat'and serving for a cooling ef-j passagethrough the coils 39 and 38, and being heated inthepreliminary orprimary heater 13 to a temperature such as 700-800 F., Withoutany.appreciable cracking effect; the superheater or storage heater 19 may bemaintained at a temperature 1 3.

(such as 90O"1000o F.) slightly above that required for a cracking orother endothermic action uponl the oil fed through the pipe 12,

or-its equivalent; and the valved inlets 18a-18e may be so spaced andadjusted as -to maintain throughout the cracking coil 11,notwithstanding an absorption of heat vltherein, a desired temperaturegradient r `quantities as neither to occasion an excessive rise nor topermit an excessive drop in the temperature of the treated oil withwhich said re-circulated oil may be admixed. t For the purposes referredto, I may ordinarily use about three parts of, said re-circulated o'il Ato one part of the treated oil.

not onl rI`he pipes employed in the .cracking coil 11, although perhapsordinarily reaching a total length such as 50G-150() feet, are intend-yed to havev a diameter (as, a diameterof 6, to 12") assuring continuousflow `therethrough; and ythe rate of said continuous flow may be such asto ',assure an advance of the resultant mixture at a rate such as one ortwo feet per second, or at a rate assuring a maintenance of the desiredtemperatu-re for a period such as 5-15 minutes, and obviatin depositionof caibom-about 200300 lbs. pressure being maintained The mixture of rawoil and re-circulated thermolyzed oil (or other liquid employed as a.medium for the transfer of heat) being preferably kept mainly orentirely in the liquid phase up to the time of its advance past thevalve 23 or its entry into the vaporizer 24, an out-let pressure notexceeding about 50 pounds anda temperature such as 650 may e maintainedin this element,-an outlet pressure not exceeding about 50 pounds, and atemperature between about 400`and 550o F., being then` appropriate tothe separator 35. or its equivalent. I

It will be obvious that the foregoing 'temperatures are mere`approximations,the limits of variation tolerated being dependent uponthe character of the raw oil treated ibut upon the specic productdesired, and the described method being entirely suitable to use in theproduction of either gasoline, or kerosene, or lubricating oils andcapable of use not only with heavy and/or intermediate oil fractionsofwidely different types but also capable of use with otherre-circulated heatin mediums, such as molten salts or metals; ut my useof socalled thermolyzed oil or other'relatively stable oil or oilmixture as a heating medium has the important advantage that it not onlyfavors production and separation of the desired products from the rawfoil but incidentally augments the quantity of said products, by eithera rapid or a gradual cracking of the heat-transferring mediumitself,'-although the temperatures maintained respectively in thepreliminary heater 13 and the superheater 19, as related to the crackingtemperatures of the respective oils circulated therethrough, may be,under the conditions described, such as to result in only a very'slightor slow accumulation of carbon therein or in the cracking coil 11.

At the time operations are begun, an oil suitable for use as aheat-transferring medium may be advanced from any convenient source (as,for example, from the storage Y tank 45) to the superheater 19,simultaneously with the advance of raw oil, to be cracked, through thepipe 12; as soon as regular operation is under way, any desiredproportion of the residual oils or bottoms which accumulate in the lowerportionsof vaporizer 24 and/or separator 35 may be returned, bymentioned connections, through the pipe 28 and pump 29; and, in order toprovide for eitheran automatic or a manual control of such return, andalso for yarying the output of residuum or bottoms through the valvedpipe 34 (which `may lead to a fuel oil storage tank, not shown) andthrough the valved pipe 42 (communicating with the tank 45) I show thebottom outlet 26 and intermediate outlet g 43 of the separator 35 asrespectively pro- ,vided not only withmanual valves 48 and 48 but alsowith liquid-level-controlled automatic valves 50 and 51,--these latterbeing adapted, even though the valves 48 and 4X8 be kept Wide open, tomaintain a predetermined level of oil in said vaporizer and in a part ofsaid separator respectively.

In case exclusive reliance were to be placed upon the automatic valves50 and 51, some of the mentioned pipes and/or valves might be dispensedwith; but I consider it advantageous to provide all of the saine, inorder to permit reliance upon the manual valves 48 and/or 49 to controlbottom outlets; in order to predetermine'an upper limit of residuum orbottoms or intermediate fractions accumug lating in the vaporizer and/orthe separator;

and in orderto facilitate such variations in through the cracking coilywith (say) 3,000 vbarrels of a recirculated heavy intermediate oil mayyyield (say) 350 barrels of gasoline (via- 37) 500 barrels of a lubricantor other intermediate oil (via 34') and about 150 barrels of fuel oilvia 34; but it should be understood that the recirculated oil may be ofeither higher or lower gravity and specific heat than the raW oil thatis cracked by transbe disposed of (as fuel oil, or the like) orr used'as a recirculated heat-transferring medium during a subsequent runningof a quantity of less heat-reslstant oil.

By the describedmeans, some to 35%- of the raw oil initially containingno appreciable quantity of gasoline may be converted into ,a productmarketable as gasoline,the conversion being presumably distributed bc-'tweenthe successive sections of a Icracking coil of the generalcharacter described; but I call attention not only tothe high percent- Yage of gasoline and/or kerosene recovery and to the co/trollability,versatility and simplicity of the described apparatus andnietho'd butalso to the fact that said apparatus and method are such as to permitoperation for long periods (amounting to months, as against days orWeeks in the case of other t-ypesof apparatus currentl em lo ed) be- .'YP Yn tween shut-downs for purposes of cleaning;-

out deposits of carbon, or the like.

Although I have herein described a single mfcompletembodiment of myinvention, 4in;

cluding various optional features and sug-L gesting alternativeconnections and modes of operation, it should be understood not only (l)that I placeespecial emphasis upon my vuse of recircu-lated, relativelystable oil,`

added in successive increments and at a high temperature to a stream of,oil Nto be cracked thereby, and (2) that various features; of myinvention may be capable of independent use, but also (3) that numerousmodifications of both my apparatus and my yprocess might easily bedevised, by those skilled in the artsi to which this case relates,Without involving the slightest departure from the spirit and scope ofmy invention, as the Asame is indicated above and in othe followingclaim but only in the limiting case Will a total uantity oftheheat-transferrin oil be added-at lone time to the oil to be crac ed.

I clai'm as my invention:

sure, the `first-mentioned mineral oil mayfbe cracked; and advancingsaid medlum', -while so heated, into direct contact with" saidfirstmentioned mineral oil and thence, after a,` i

application of heat, subsequently to said contact, to saidfirst-mentioned oil, for the desired cracking effect.

2. A method of cracking mineral oil which comprises: heating a fluentheat transferrlng medium in the form of a relatively stable oil to atemperature above the ,temperature at which, under the given conditionsof pressure, the first-mentioned unineral oil maybe cracked; advancingsaid medium, While so heated, into direct contact with said mineral oiland, after a sufficient time to permit a cracking reaction: at theresultant temperature, into a region of relatively less pressure;and'taking off resultant vapors from said last-mentioned region,-thetemperature of the relatively stable oil being such' as to obviate otherapplication of heat, subsequently to said contact, to saidfirst-mentionedI oil, forthe desired cracking effect.

3. A `method of cracking a mineral oil which comprises: yheating aiiuent heat-` transfer medium to a temperature above the temperature atwhich, under the given com ditions of pressure, the said mineral oil maybe cracked; advancing said medium, ivh'ile so heated, into directcontact with saidmineral oil; advancing the mixture of-said medium andsaid oil in a stream, then separating re- Sultant vapors, and(lreturning residues there- .y

by obtained for use, in like manner, as a heattransfer medium, in thecracking of an additional quantity of mineral oil.

4. A` method of cracking a mine-ral oil which comprises Lheating' aheat-transferring medium, in the form of a heavy oil, to atemperatureabove that at which, under the given conditions of pressure,the said lmineral oil may be cracked; vadvancing said medium iiiseparate increments and While so heated,into a stream of said mineraloil; and taking off resultant vapors. Y

f 5'. A method of cracking mineral bil which comprises: heatinga streamofsaid mineral 011 and a stream of afluent,heat-transferring medium,inthe form of' a relatively stable 4oil, respectively Vto a temperature-belOW and to a\temp'erature above the cracking temperature of saidmineral oil; and commmgling said streams during a continuedJ advancethereof. f

6. A nethod of cracking a 'mineraP oil l'. method ofcracking mineral oilwhich LWhich comprises-e heatinga stream of said mineral oil and astream of a fluent heatcomprises: heating a iuent heat-transferringmedium in the form of a relatively stable oil,

to a temperature above the temperaturel at which, under thegivenconditions of presb elow and to a temperature above the' crack-I ilo ingtemperature of said mineral oil; and commingling said streams by addingsaid medium to said oil, during a continue advance thereof, insuccessive increments and at points spaced along said` mineral oilstream.

7. A method of elevating a mineral oil, largely liquid, to .a crackingtemperature While minimizing the formation of undesired productstliereinqvhich comprises: bringing into direct contact therewith, duringcontinued advance, a body of a stable oil Which contains sufficient heatto elevate said mineral oil to a cracking temperature,-the resultantadmixture being advanced, mainly still in liquid phase and Withoutexternal application of heat thereto subsequently to the mentionedcontact, toward a point of vaporization of lighter products at a lesspressure.- Y

8. A method of elevating a mineral oil t kaiJ cracking temperature Whileminimizing the formation of undesired products thereinyWhicheccomprises: bringing into direct contact therewith a body of astable oil which contains sufficient heat to elevate said mineral oil toa cracking temperature by flowing onejof saidoils into a continuouslyadvancing stream of the other of said oils, the heat in the relativelystable oil being suflicient, at the time of thel mentioned contact, toproduce a cracking temperature in the mineral oil, Without subsequent,external Y applicationof heat.

9.J A method of elevating a Amineral oil to a cracking temperature Whileminimizing the formation of undesired products therein Which comprises:bringing into direct contact therewith a body of a stable oil whichcontains suliicient heat to elevate said mineral oil to a crackingtemperature by flowing said stable oil into a stream' of said mineraloil in separate increments ad ed at successive points along the course osaid stream, said increments being so spaced and so proportioned astomaintain a desired temperature in said stream for a predetermined time.

10. A method of imparting to an oil that heat which is required toeffect a desired endothermic reaction therein Which comprises: heatinganother and more stable oil to a temperature above that prerequisite tothe mentioned vendothermic reaction; and

thereafter directly admixing said oils, during continued advance ingenerally concurrent flow and Withoutrsubsequent application. of heat,in proportions predetermined with reference to the thermal requirementsof-said reaction.

1l. A method of the general character defined inclaim l() in Which thesecond-mentioned oil is heated to a temperature but slightly -above thementioned prerequisite temperature. l i

12. A process'of the general character defined in claimwflO in which thesecond-mentioned oil is an oil which is relatively insusceptible to thementioned endothermic reaction.

, 13. A method of the general character defined in claim l0 in which thesecond-mentioned' oil is angoil of higher specific heat than the firstmentioned oil.

14. A method of the general character defined in claim 10 in-Which thesecond-mentioned oil contains residual fractions obtained by theseparation of a desired product from a mixture previously produced inthe manner set forth in said claim.` i

15. A method of the general character delined in claim 10 in which thedesired temperature is maintained, for a predetermined period, by makinga series of small additions of said second-mentioned oil at successivepoints along the course of a stream of said first-mentioned Oil.

16. A process of the general character de-V fined in claim l0 in Whichsaid oils are respectively heated, before they are .brought intocontact, to temperatures respectively below and above the crackingtemperature of said'first-mentioned oil, and in which a separation ofdesired products from a resultant mixture is effected by stepscomprising a delivery ofthe same, at a diminished pressure, into avaporizer. l

17. In means for the cracking of mineral oils: a superheater; a crackingcoil comprising separate consecutive sections; means for delivering aliquid heat-transferring medium from said superheater, and in separatesmall streams, into said sections; means for forcing the oil to becracked into a first of said sections; means for separating vapors froma resultant mixture; and means for repeatedly returning a heavy residue,through said superheater, to serve as said heat-transferring medium insaid cracking coil.

18:'A method of cracking a mineral oil Which comprises: heating a streamof a heattransferring medium While out of contact with said mineral oilto a temperature above the temperature at which said mineral oil may becracked; advancing said stream of heat-transferring medium While soheated into direct contact With a separately advancing stream of saidmineral oil, to heat the latter during itsadvance and Without subsequentapplication of external heat; separating resultant vapors from theresidue fractionating the vapors; and employing at least a portion ofbottoms from the vapor fractionation as said heat-transferring medium.-

19. A method of cracking a mineral oil which comprises: heating a streamof a heat'- transferring medium While out of contact with said mineraloil to a temperature above the temperature at which said mineral oil maybe cracked; advancing said stream of heat-transferring medium While soheated into direct contact with a separately advancing stream of saidmineral oil, to heat the latter during its advance and withoutsubsequent application of external heat; separating`resultant vaporsfrom the'residue; fractionating the vapors; andC employing at least aportion of the resultant bottoms, together with atleast a portion ofsaid residue, as said heattransferring medium. j

In testimon whereof, I have hereunto set my hand at os Angeles,California, this 15th day of November, 1926. f) u JOHN B. .JAQUA.

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